JPS6350657A - Fuel supply system for internal combustion engine - Google Patents

Abstract

PURPOSE:To avoid getting a time lag as well as to aim at improvement in engine performance, by controlling heating of an air-fuel mixture and vibration of fuel on the basis of an engine warm-up state and a combustion state by spectrum analysis of flame light to be produced in a combustion chamber. CONSTITUTION:The detected value of a water temerature sensor 19 and each detected value of photoelectric transfer elements 24 and 25 are being inputted into a control unit 27. Combustion light in a combustion chamber 13 is inputted in these photoelectric transfer elements 24 and 25 via optical fibers 29, 21, a red transmissive filter 22 or a blue transmissive filter 23. The control unit 27 controls an electric heating source for an air-fuel mixture and vibration of the piezoelectric element 18 attached to a riser part of a suction pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply device for an internal combustion engine, and particularly to a device for improving air-fuel mixture properties by appropriately changing the heating state of intake air or the vibration state of supplied fuel. .

(Prior art) In general, when the engine is not warmed up, the air-fuel mixture properties, that is, the atomization state of the fuel, are not necessarily good, and insufficient atomization of the fuel causes liquid fuel to flow into the combustion chamber, causing the engine to This may cause a stall. For this reason, a method is adopted in which an intake air heating device is used to increase the intake air temperature and improve the air-fuel mixture properties.

Such intake air heating devices include, for example, a hot water heating type that uses the engine's A-added water as a heat source, and an exhaust heating type that uses engine exhaust heat as a heat source. However, in the former case, it takes time for the coolant temperature to rise when the engine is cold started, and intake air cannot be heated during that time. Furthermore, in the latter case, even after the warm-up is completed, the intake air is heated more than necessary, so there is a problem that percolation occurs in the fuel supply system. Therefore, intake air heating devices with easily controllable electrical heating sources are commonly employed.

As a conventional fuel supply device equipped with this type of intake air heating device, for example, the one shown in Fig. 7.8 is known (
(See Japanese Patent Application Laid-Open No. 59-215928). In FIG. 7, 1 is a diesel engine, intake air is supplied to each cylinder through an intake pipe 2, and fuel is supplied to a fuel injection pump 3.
The liquid is then injected from the injection nozzle 5 via the injection pipe 4. Then, the atomized air-fuel mixture in the thin chamber 6 is self-ignited and combusted by the heat of compression during compression, and is discharged through the exhaust pipe 7 as exhaust gas. The rotation speed N of the engine 1 is detected by the rotation speed sensor 8, and the combustion light inside the engine 1 cylinder is detected by the flame sensor 9.
Detected by Signals from the rotational speed sensor 8 and flame sensor 9 are input to a control unit 10, and the control unit 10 performs various controls on the engine based on information from these sensors.

That is, as the flowchart is shown in FIG.
At P, the engine rotation speed N is detected by the rotation speed sensor 8, and at P2, the basic maximum injection amount is calculated based on this rotation speed N, etc. Then, at P, the flame sensor 9 detects the intensity of the engine's combustion light at that time, and at P4, the change in outside atmospheric pressure is estimated based on the intensity of the combustion light, and the basic maximum injection amount calculated at P2 is corrected. are doing.

(Problems to be Solved by the Invention) However, such conventional fuel supply systems for internal combustion engines have a configuration that detects the overall intensity of flame light generated within the combustion chamber and corrects the fuel injection amount. Because it became
It has not always been possible to detect a sufficient combustion state, and it has been difficult to suppress the occurrence of smoldering and liquid combustion.

In addition, since B simply controlled intake air heating as a method to improve the air-fuel mixture properties, there may be a time delay in promoting fuel atomization, especially during low-temperature starts and transient operation, resulting in fuel efficiency. This may lead to deterioration or a decrease in output.

(Objective of the Invention) Therefore, the present invention detects flame light generated in a combustion chamber, analyzes the spectrum of this flame light, and appropriately determines whether the combustion state is good or bad at that time, and according to the result of this determination. By manipulating the properties of the air-fuel mixture by heating the intake air-fuel mixture or vibrating the supplied fuel, it is possible to reduce fuel consumption and improve output by avoiding the occurrence of liquid combustion and the time delay in promoting atomization. The purpose is

(Means for Solving the Problems) In order to achieve the above object, the fuel supply system for an internal combustion engine according to the present invention detects light generated within the combustion chamber of the engine, as the basic conceptual diagram is shown in FIG. A light detection means a, a warm-up state detection means for detecting the warm-up state of the engine, a spectrum discrimination means C for determining the spectrum of light due to combustion based on the output of the light detection means a, and a warm-up state of the engine. and a control means d for calculating a control value for controlling the heating state of the intake air-fuel mixture or the vibration state of the supplied fuel so as to change the properties of the air-fuel mixture based on the spectrum of light caused by combustion, and based on the output of the control means d. and operating means e for controlling the properties of the air-fuel mixture by heating the intake air-fuel mixture or vibrating the supplied fuel.

(Function) In the present invention, the quality of the combustion state at that time is appropriately determined from the spectrum of the flame light generated in the combustion chamber, and the intake air-fuel mixture is heated or the supplied fuel is vibrated depending on the result of this determination, so that the air-fuel mixture is heated. properties are appropriately manipulated. Therefore, occurrence of liquid combustion and time delay in promoting atomization are avoided, and deterioration of fuel efficiency and reduction in output are prevented.

(Example) Hereinafter, the present invention will be explained based on the drawings.

2 to 4 are diagrams showing a first embodiment of the present invention, and this embodiment is an example in which a bandpass filter is used as a spectrum discrimination means. First, the configuration will be explained. In FIGS. 2 and 2, 11 is an engine, and 12 is a cylinder head. An intake port 14 communicating with a combustion chamber 13 is formed in the cylinder head 12, and the intake boat 14 is opened and closed by an intake valve 15. An intake pipe 16 having an intake passage 16a that communicates with the intake boat 14 is connected to the cylinder head 12. An electric heating source (an electric heating source) for heating the intake air is located in the upper part of the riser portion 16b in the figure in the intake passage 16a.
An operating means) 17 is provided. Further, a piezoelectric element 18 that vibrates the supplied fuel is provided in the riser part 16b of the intake pipe 1G and the intake boat 14, and the temperature T of the cooling water flowing through the water jacket is measured with respect to the water temperature sensor (warm-up state detection means) 19. Detected.

Combustion light in the combustion chamber 13 is connected by an optical fiber 20.21 to a photo-electric conversion element 24.25 via a bandpass filter (transmitting red) 22 or a band pass filter (transmitting blue) 23, respectively. The above optical fiber 20.2
1. The bandpass filters 22 , 23 and the photo-electric conversion elements 24 , 25 constitute a light detection means 26 , and signals from the light detection means 26 and the water temperature sensor 19 are input to a control unit 27 . Further, the bandpass filters 22 and 23 have a function as a spectrum discrimination means 28 together with the control unit 27, and also have a function as a control means by themselves, and are constituted by a microcomputer. Then, the control unit 27 performs spectrum discrimination based on sensor information from the flame sensor 9 according to a program stored in an internal memory, and calculates processing values necessary for fuel supply control.

Further, 30 is an injector in the case of an EGT engine.

Next, the effect will be explained, but first, the influence on combustion light due to a change in air-fuel mixture properties will be explained using gasoline as an example.

As shown in FIG. 3, in general, when the air-fuel mixture properties (the atomization state of the supplied fuel) are good and the combustion state is good, the flame is blue-white and slightly dark (see the solid line in the figure). Furthermore, if the charging efficiency is increased and the torque is increased in this state, the flame will remain bluish-white and its brightness will increase. On the other hand, if the air-fuel mixture properties are poor or if liquid fuel remains on the valve surface or other parts of the cylinder, the flame emits a bright red light (see the dotted chain line in the same figure). Furthermore, red flames are particularly likely to be detected when the spark plug is covered with fuel or when the engine is at a low temperature (for example, when the water temperature after starting is 50° C. or less) and the combustion condition is poor.

In this embodiment, in view of the above-mentioned characteristics of the combustion state and combustion light, we focused on the fact that the flame generates red light in particularly inefficient combustion states, and used the program shown in FIG. 4 to be described later. The properties of the mixture are appropriately controlled.

That is, the mixing state of fuel and air is detected based on the intensity ratio of red light and blue light of the combustion light, and in the case of the EGI method, the mixing state of the fuel and air is detected based on the intensity ratio of red light and blue light of the combustion light. Appropriate operation is performed by vibration, or in the case of the carburetor system, by both the vibration of the piezoelectric element 18 attached to the intake boat 14 and the riser portion 16b and the heating of the electric heating source 17. Therefore, the combustion state can be improved quickly and effectively.

FIG. 4 is a flowchart showing a fuel supply control program based on the above basic principle, and P and PI6 in the figure indicate each step of the flow. This program is executed once every predetermined time.

The light generated by combustion in the combustion chamber 13 is transmitted through 62 (7
) is transmitted to each bandpass filter 22.23 through one end face of the optical fiber 20.21.

At this time, if the fuel in the mixture is not sufficiently atomized, the mixture ratio of the mixture becomes partially overrich as described above, and compared to the case where the fuel is completely atomized, As shown in the figure, it is known that the combustion emission spectrum shifts to the longer wavelength side (red side).

Therefore, two types of bandpass filters are prepared in advance, a blue light transmitting type and a red light transmitting type, and the output signals of each color are converted to electrical No. 43 using a photo-electrical conversion element, and the intensity ratio IJI/ TI (However, I: Red light signal, ■8:
blue light signal). In addition, in advance, the memory of the control unit 27 is set to 0N10FF to energize the piezoelectric element (piezo vibrator) 18 and the electric heating source 17 under predetermined conditions.
Enter the value of the spectral intensity ratio ■c of the predetermined level to be determined (.

In this way, the intensity ratio I, l/In, and the svector intensity ratio I are compared at Pl+, and when I R/I n exceeds ■0 continuously for N cycles or more, the piezoelectric element 18 is activated at P1□. PI3 to PI5 control the power supply to the electrical heating source. Do step 11. That is, at P1□, the piezoelectric element 18 attached to the intake boat 14 and the riser portion 16b is energized to vibrate the supplied fuel. Also, p
At H, the engine cooling water temperature T at that time is compared with a predetermined set value To, and when T<To, the electric heating source 17 is energized at pz to atomize the liquid fuel, and T≧TO. In this case, PIS stops power supply to electrical heating #17. on the other hand,
When IR/IIl at pH falls below I continuously for N cycles, the control unit 27 outputs a signal to stop energizing the piezoelectric element 18 at PI6.

Therefore, the intensity ratio IR/IB of the red light signal IM and the blue light signal In representing the combustion state at that time exceeds the predetermined value I continuously for the number of light emission cycles N, and the cooling water? When n T is less than To, the electrical heating source 17 and the piezoelectric element 18 are activated by the output signal from the control unit 27.
Both are energized and fuel atomization is promoted. here,
The optimum value for the number of light emission cycles N is selected in advance for each engine and stored in the control unit 10. Further, the intake air is heated, atomization of the fuel is promoted, and the intensity ratio IR/II becomes a predetermined value ■. When the cooling water temperature T becomes lower than the number of light emission cycles N continuously, the cooling water temperature T becomes T.
Even if the temperature is below o, the electric heating source 17 and the piezoelectric element 18 are de-energized by a signal from the control unit 10, and heating and vibration of the intake air are stopped.

In this way, in the fuel supply system of this embodiment, the flame light inside the combustion chamber is detected and transmitted using two optical fibers, and two band-pass filters for transmitting blue or red and a photo-electric conversion element are used. By using a The properties of the air-fuel mixture are appropriately controlled by the vibration of the piezoelectric element or the heating of the electric heating source.6 Therefore, the two operating means of vibration of the supplied fuel and heating of the intake air-fuel mixture are used in combination depending on the combustion state of the engine. This makes it possible to appropriately avoid unmixed fuel conditions and delays in atomization.
It is possible to prevent plug fogging and engine stalling in an unwarmed state or during transient operation. Furthermore, since the intake air is not heated when the air-fuel mixture is in a good atomization state, it is possible to suppress unnecessary power consumption by the intake air heating device and reduce the burden on the battery.

Furthermore, since the air-fuel mixture properties are not good when starting at a low temperature, the amount of fuel was increased slightly to make it rich, which caused soot and C.
Although large amounts of Hx and CO were likely to be generated, the present invention promotes atomization of fuel regardless of temperature, so generation of such soot, CHx, and Co can be prevented. As a result, the combustion state of the engine can always be maintained in an optimal state, and it is possible to reduce fuel consumption, improve output, and improve exhaust emissions at the same time.

Note that this embodiment uses two methods for determining the spectrum of combustion light.
Although two bandpass filters are used, the present invention is not limited to this. The point is that it is sufficient to appropriately detect the spectral components of the combustion light representing the combustion state, so it goes without saying that, for example, a prism may be used instead of a bandpass filter to separate the combustion light. In this case, there is an advantage that only one optical fiber is required.

Further, in this embodiment, the parameters of the spectral distribution are represented by blue and red, but other colors (wavelengths) may be used, and it is of course possible to use two or more colors.

FIG. 5.6 shows a second embodiment of the present invention, in which an optical fiber for receiving combustion signals is shared and integrated with the spark plug.

Components that are the same as those in the first embodiment are given the same numbers and their explanations will be omitted.

In No. 5M, 31 is a spark plug common type optical fiber sensor, and specifically, the spark plug common type optical fiber sensor 31 has a tip portion 31a that detects light, and a tip portion 31a that detects light, as shown in a cross-sectional view in FIG. It is formed by the transmitting quartz part 31b and the glass seal 32, and is inside the center electrode 33. of the spark plug 33. It is installed inside the l.

By doing this, in this embodiment, the optical fibers 20 and 21 and the bandpass filter 2 shown in FIG.
2.23 and the photo-electric conversion elements 24.25 can all be incorporated into the spark plug 32 and integrated.

(Effects of the Invention) According to the present invention, the spectrum of flame light generated in the combustion chamber is analyzed to appropriately determine whether the combustion state is good or bad at that time, and the intake air-fuel mixture is heated according to the result of this determination. Alternatively, since the supplied fuel is vibrated to appropriately control the properties of the air-fuel mixture, it is possible to avoid the occurrence of liquid combustion and the time delay in promoting atomization, thereby reducing fuel consumption, increasing output, and improving exhaust emission characteristics. can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a basic conceptual diagram of the present invention, Figs. 2 to 4 are diagrams showing a first embodiment of the invention, Fig. 2 is an overall configuration diagram thereof, and Fig. 3 is a diagram showing the relationship between light intensity and wavelength. FIG. 4 is a flowchart showing the fuel supply control program, FIG. 5.6 is a diagram showing the second embodiment of the present invention, FIG. The figure is a sectional view of the optical fiber sensor, Figure 7 is an overall configuration diagram of a conventional fuel supply system, and Figure 8 is a cross-sectional view of the optical fiber sensor.
The figure is a flowchart showing a conventional fuel supply control program. 11... Engine, 26... Light detection means, 27... Control unit (spectrum discrimination means, control means), 28... Spectrum discrimination means).

Claims (1)

[Scope of Claims] a) light detection means for detecting light generated in the combustion chamber of the engine; b) warm-up state detection means for detecting the warm-up state of the engine; and c) based on the output of the light detection means. d) spectrum discrimination means for discriminating the spectrum of light caused by combustion; and d) a heating state of the intake air-fuel mixture or vibration of the supplied fuel so as to change the properties of the air-fuel mixture based on the warm-up state of the engine and the spectrum of light caused by combustion. A control means for calculating a control value for controlling the state; and e) an operation means for heating the intake air-fuel mixture or vibrating the supplied fuel based on the output of the control means to manipulate the properties of the air-fuel mixture. A fuel supply system for an internal combustion engine featuring features.